https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114668
Bug ID: 114668
Summary: [14] RISC-V rv64gcv: miscompile at -O3
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: patrick at rivosinc dot com
Target Milestone: ---
Testcase:
char a;
int b;
short e[14];
char f[4][12544];
_Bool c[4][5];
int main() {
for (int i = 0; i < 4; ++i)
for (int l = 0; l < 15; ++l)
for (int m = 0; m < 15; ++m)
f[i][l * m] = 3;
for (int j = 0; j < 4; j += 1)
for (int k = 3; k < 13; k += 3)
for (_Bool l = 0; l < 1; l = 1)
for (int m = 0; m < 4; m += 1) {
a = 0;
b -= e[k];
c[j][m] = f[j][6];
}
for (long i = 2; i < 4; ++i)
__builtin_printf("%X\n", c[3][3]);
}
Commands:
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc
> -march=rv64gcv -O3 red.c -o red.out
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/qemu-riscv64 red.out
1
FF
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc
> -march=rv64gcv -O2 red.c -o red.out
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/qemu-riscv64 red.out
1
1
Adjusting the f array to its minimal size of f[4][255] makes the issue go away.
Looks similar to pr114665 so this might be a duplicate/related. Submitting this
bug in case it's easier to understand the root cause.
Found via fuzzer.
